Let-off mechanism for looms



Oct. 20, 1936.- QDBROWN 2,058,127

' LET-OFF MECHANISM FOR LOOMS- Filed May 1, 1936 INVENTOR.

C'AEL D. 5Eow/v BY I @M {M ATTORNEY.

Patented Oct. 20, 1936 PATENT OFFICE LET-OFF MECHANISM FOR LOOMS Carl D.Brown, Hopedale, Mass, assignor to Draper Corporation, Hopedale, Mass.,a corporation of Maine Application May 1, 1936, Serial No. 77,402

Claims. (Cl. 139-100) This invention relates to looms and moreparticularly to means for controlling the'rate at which the warp sheetis let off from the warp beam as the weaving progresses.

Let-off mechanism has been provided in which the rotation of the warpbeam is controlled by means operating in timed relation to the othermechanism of the loom, and under control of the various devices forgoverning the rate of rotation of the warp beam in accordance with thetension of the warp sheet. Such let-off mechanisms have usually beenoperated only once during each complete reciprocation of the lay, thatis, once for each pick. I 4

Under some conditions the action of the takeup and of the sheddingmechanism combine to produce such a tension on the warp sheet that itbecomes desirable that the let-off operate more frequently than once foreach pick. v r 2 An object of the present invention, accordingly is toprovide an improved let-off mechanism with simple and efficientcontrolling devices for causing the let-off operation a plurality oftimes during each reciprocation of the lay. As illus-' trated, thepresent invention provides a single operating member for causing thelet-off mechanism operation to take place twice during eachreciprocation of the lay.

In the drawing,

Figure 1 is a view in side elevation of a loom showing a let-01fmechanism embodying a preferred form of the present invention;

Figure 2 is a detail view showing in full and dotted lines the positionswhich the parts of the let-off mechanism assume during the forwardmovement of the sword; and,

Figure 3 is a detail view similar to Figure 2 showing the positions ofthe parts during return movement of the sword.

The parts of the loom as illustrated may be supported between loomsides2 which may be of any usual form and construction. A reed 4 is carriedby a lay 6 which is mounted upon swords 8. The swords 8 are mounted forreciprocation toward and away from the front of the loom by a crank l0and a pitman l2 as is usual in machines of this type.

The warp sheet passes from a warp beam, indicated generally at l4, overa whip roll l6, through harnesses l8, andthrough the reed 4. The clothas it is woven may be taken up by any conventional form of take-upmechanism now well known in the art. The take-up mechanism and theharness operating mechanismare not de- 55; scribed herein since they arenot essential to a complete understanding of the present invennun.

The warp beam I4 is provided at one end with a head 20 having gear teethout therein which cooperate with the teeth of a pinion (not shown). Thepinion is fixed upon a shaft 24 which is driven by internal gearingcontained within a housing 26 which is operated by a ratchet wheel 28.The parts referred to just above are not described in detail hereinsince they are described and claimed in United States Patent No.647,815, granted April 1'7, 1900 to W. F. Draper and C. F. Roper towhich reference may be had for a more detailed description.

The whip roll I6 is mounted in arms 30 on a rock shaft 32 journalled. inthe loom frame. The rock shaft 32 is provided with an arm 34 which ispivoted at 36 to one end of a link 38. The other end of the link 38passes through an opening formed in a bracket 40 secured to the loomside2. A spring 42 surrounds the link 38 and is interposed between thebracket 40 anda collar on the link to yieldingly urge the whip roll l6against the Warp sheet. The lower end of the link 38 is bent over andengages the front of a lug 44 on a lever 48 which is pivoted at 46 tothe bracket 40. lever 48 extends downwardly and is pivotally connectedby a suitable stud (not shown) to an oscillating pawl carrier 50. Thepawl carrier 50, as shown, is in the form of a lever fulcrumed on theshaft 24. The above mentioned pivotal connection may be positioned andcontrolled as in the above mentioned patent to Draper et al. A spring 52is connected at one end to the lever 48 and at its other end to an arm54 fixed to the bracket 40.

By this construction, it will readily be understood that the spring 52serves yieldingly to urge the lever 48 in a clockwise direction and thusto urge the pawl carrier 50 in a counter-clockwise direction. Movementof the pawl carrier 50 in a counter-clockwise direction serves to drawthe pawl 56 over the teeth 58 of the ratchet wheel 28 and to positionthe pawl 50 for an operating stroke. This counter-clockwise or returnmovement of the pawl 50 is limited by the bent end of the link 38. Thatis, the spring 52 will move the lever 48 in a clockwise direction untilthe lug contacts with the bent line of the link 38, the position ofwhich is controlled by the tension of the warp sheet. 1 l

I have provided mechanism operating in timed relation to the lay forimparting to the pawl carrier two operating strokes during the intervalrequired for the lay to make one complete recip- The rocation. Apreferred form of this mechanism will now be described.

The lower end of the pawl carrier lever 56 is pivotally connected at 66to one end of a substantially horizontal rod 62. The other end of thisrod 62 is pivotally connected at 64 to the lower end of a lever 66 whichis fulcrumed at 68 on a. bracket 16 fastened to the loomside 2. Anactuating member 12 is secured to the sword 8 by a machine screw 13, andis provided with a pair of outwardly projecting lugs 14, 16. The lugsare arranged on opposite sides of the lever 66 with the lower lug Hilocated below the fulcrum 68 of the lever 66 and the upper lug locatedabove the fulcrum 68. When the lay 6 moves'in the direction indicated bythe arrow in Figure 2, the lug 14 engages the lever 66 and rocks it in aclockwise direction. When the lay 6 moves in the opposite direction, asindicated by the arrow in Figure 3, the upper lug 16 engages the lever66 and rocks it in a clockwise direction. The spring 52 between thesemovements of the lever 66 has operated to move the lever 66 and the pawlcarrier 56 connected thereto in a counter-clockwise direction asdescribed above. It is to be noted that the lugs l4, 16 on the actuatingmember 12 are so arranged that they engage the lever 66 to move it in aclockwise direction only during part of the reciprocating movement ofthe lay 6. This is accomplished by so spacing the lugs 14, 76 away fromthe lever 66 that there is lost motion between these parts.

Referring now to Figure 2, the parts shown in full lines are in theposition they assume when the lay 6 is in its extreme forwardposition.At this time the lug "i4 is in engagement with the lever 66. The lug 16at this time does not engage the lever 66. When the lay 6 begins itsreturn movement, the spring 52 operates to return the lever 66 andthepawl carrier 56 connected thereto to starting position. After thisreturn movement has been completed, and the parts are in thepositionshown in dotted lines in Figure 2, the upper lug 16, oncontinued return or rearward movement of the lay 6, contacts with thelever 66 to impart a second clockwise movement to the lever 66 and thepawl carrier 56.

Movement of the lever 66 in a clockwise direction continues until theparts occupy the positions shown in full lines in Figure 3. At thistime, the pawl carrier 56 has been advanced to the end of its operatingstroke and the lug 16 is still in engagement with the lever and the lug14 is out of engagement therewith. When the lay 6 is moved from thisback position toward its mid position as shown in Figure 1, the spring52 will operate to move the lever 66 and the pawl carrier 56 in acounter-clockwise direction to return the pawl carrier 56 and the lever66 to the position shown in dotted lines in Figure 3. Dur ing themovement of the parts from the dotted line position shown in Figure 2 tothe dotted line position in Figure 3, the lower lug M has not been inengagement with the lever 66. When the lay 6 continues its forwardmovement, the lug 14 will come into engagement with the lever 66 andwill rock the lever and the pawl carrier 56 in a clockwise direction tooperate the let-off mechanism.

Although the invention has been described in detail, it may be well fora clearer understanding of the invention, to review the operationof themachine, briefly. Beginning the cycle of operation of the lay 6 at theextreme back position as shown in full lines in Figure 3, the lay 6 ismoved forwardly to the full line position shown in Figure 2. During thefirst portion of this movement, the spring 52 operates to move the lever66 in a counter-clockwise direction to return the pawl carrier 56 to thedotted line position shown in Figure 3. After the pawl carrier has beenreturned to this position, the lug 14 engages the lever 66 and rotatesit in a clockwise direction to impart to the pawl carrier 56 itsoperating stroke to rotate the beam and. let off the warp sheet. Theparts continue this movement until the lay 6 reaches its extreme forwardposition, as shown in full lines in Figure 2. The lay 6 then begins itsreturn movement and the spring 52 operates to return the lever 66 andthe pawl carrier 56 connected thereto to the position shown in dottedlines in Fig. 2. The upper lug then engages the lever ,66 to impart anoperating stroke to the pawl carrier 56. This return movement iscontinued until the parts are returned to the position shown in fulllines in Figure 3, thus completi ng the reciprocation of the lay 6. Itis apparent that the let-off mechanism is positively operated twiceduring a single reciprocation of the lay 6.

Although the invention has been described with particular'reference tothe mechanism disclosed in the drawing, it is evident that the inventionis not limited thereto, and that other mechanism could be employed if sodesired.

Having'thus described my invention, what I claim as new and desire tosecure by Letters Patent of the United States is:

1. In a loom having a frame, a reciprocating lay and a warp let-offmechanism, said let-off mechanism including gearing operated by a singleratchet wheel for controlling the advance of a warp sheet, anoscillating pawl carrier for moving said ratchet wheel, an actuatingmember fixed with respect to said lay, and a singlemember movablymounted on the loom frame and arranged to be engaged by said actuatingmember for imparting two complete oscillations to said pawl carrier foreach complete oscillation of the lay;

2. In a loom having a frame, a reciprocating lay and a warp let-offmechanism, said mechanism including gearing operated by a single ratchetwheel for controlling the advance of a warp sheet, an oscillating pawlcarrier for moving said ratchet wheel, an actuating member fixed withrespect to said lay, and a lever fulcrumed to the loom frame andconnected to said pawl carrier, said lever being arranged to be engagedby said actuating member to receive two complete oscillations from saidactuating member during a single reciprocation of the lay.

3. In a loom, a reciprocating lay and a warp let-off mechanism, saidlet-off mechanism including gearing operated by a single ratchet wheelfor controlling the advance of a warp sheet, an oscillating pawl carrierfor moving said ratchet wheel, an actuating member reciprocating withthe lay, said member being provided with a pair of projections, and asingle means connected to saidpawl carrier arranged to be engaged bysaid projections to impart two complete oscillations to said pawlcarrier during a single reciprocation of the lay.

4. In a loom having a frame, a reciprocating lay and a warp let-offmechanism, said let-off mechanism including gearing operated by a singleratchet wheel for controlling the advance of a warp sheet, anoscillating pawl carrier for moving said ratchet wheel, an actuatingmember fixed with respect to the lay and provided with a pair ofprojecting lugs, a lever fulcrumed to the loom frame and connected tosaid pawl carrier, one of said lugs being positioned to engage the leverabove the fulcrum of said lever and the other lug being positioned toengage the lever below said fulcrum, whereby one of said lugs willengage said lever on movement of the lay in one direction to impart anoperating movement to said pawl carrier and the other of said lugs toengage said lever to impart an operating movement to said pawl carrierduring movement of the lay in the opposite direction, and yielding meansfor returning the pawl carrier to its initial position between operatingmovements, there being lost motion between said lugs and said lever topermit said return movement of pawl carrier.

5. In a loom having a frame, a reciprocating lay and a warp let-oifmechanism, said let-off mechanism including gearing operated by a singleratchet wheel for controlling the advance of a warp sheet, anoscillating pawl carrier for rotating said ratchet wheel, an actuatingmember reciprocating with the lay, said member being provided with apair of projecting lugs, a lever fulcrumed to the loom frame andconnected to said pawl carrier, one of said lugs being arranged toengage the lever above its fulcrum and the other being arranged toengage the lever below its fulcrum, whereby one of said lugs will engagethe lever on movement of the lay in one direction to impart operatingmovement to the pawl carrier and the other of said lugs will engage saidlever to impart an operating movement to the pawl carrier duringmovement of the lay in the opposite direction, and means for returningthe pawl carrier to its initial position between operating movements.

CARL D. BROWN.

